We've begun our first build so far with all wood supports. It should be finished soon after the beginning of the season. We're using platform designs from the zipline industry so they're rated for up to 8 people.
For our first entrance design we'll be using a trap door and a rope ladder with a belay safe fall arrest rope running along the side. If someone were to climb that ladder and lose their grip they couldn't fall to the ground. Because it's a fully enclosed blind you could remove the safety harness and would be free to more around the inside of the blind.
I'll be sure to post pictures once it is completed!